public class Test {
    public static void main(String[] args) {
        StringBuffer a = new StringBuffer("A");
        StringBuffer b = new StringBuffer("B");
        t(a,b);
        System.out.println(a+" "+b);
    }

    public static void t(StringBuffer a,StringBuffer b){
        a.append(b);
        b=a;
    }
}
